js动态修改页面标题

// <!-- 标题动态切换代码 Start -->
window.onload = function () {
let hour = new Date().getHours()
let str = ''
if (hour < 6) {
str = '凌晨'
} else if (hour < 9) {
str = '早上'
} else if (hour < 12) {
str = '上午'
} else if (hour < 14) {
str = '中午'
} else if (hour < 17) {
str = '下午'
} else if (hour < 19) {
str = '傍晚'
} else if (hour < 22) {
str = '晚上'
} else {
str = '夜里'
}

function c () {
document.title = document[a] ? '㋡ Hi,小伙伴,' + str + '好! [' + d + ']' : d
}

let a = document.title
let b = document.title
let d = document.title
typeof document.hidden !== 'undefined' ? (a = 'hidden', b = 'visibilitychange')
: typeof document.mozHidden !== 'undefined' ? (a = 'mozHidden', b = 'mozvisibilitychange')
: typeof document.webkitHidden !== 'undefined' && (a = 'webkitHidden', b = 'webkitvisibilitychange')
typeof document.addEventListener === 'undefined' && typeof document[a] === 'undefined' || document.addEventListener(b, c, !1)
}
// <!-- 标题动态切换代码 End -->